Conventionally, to perform head shifting actions like press-fitting/releasing action, auto-reverse action, etc. by using a cam to be driven in response to rotation of a motor, the driving force of the cam has been directly transmitted to an operating member for shifting the head by directly linking the operating member to the cam.
Such a conventional mechanism, however, has drawbacks such as that the head stops in an insecure position while shifting if the power source is interupted to stop the motor during a press-fitting action of the head by the cam and that if a user wants to do stop operation, fast-forwarding operation, rewinding operation or eject operation, he has to wait until the action for press-fitting the head is completed because forcible operations often damage heads, etc.